1. Field of the Invention
This invention relates to a novel aromatic compound having sulfonyl groups and a process for the production of the same.
2. Description of the Prior Art
A number of aromatic compounds having functional groups such as carboxyl and imide groups have hitherto been known as raw materials for heat resisting polymers. For example, pyrometallic acid (anhydride) typical of which is Kapton is known as a raw material of polyimide and an aromatic bis(etheric anhydride) is known as a raw material of polyether imide (Japanese Patent Application OPI (Kokai) No. 24242/1975. U.S. Pat. No. 4,102,905 describes an aromatic tetracarboxylic acid anhydride having sulfonyl groups which is useful as an intermediate of polyimide and which production, however, is carried out by oxidizing a sulfide with an oxidizing agent such as potassium bichromate to form its sulfone.
However, the polyimide obtained using pyromellitic acid (anhydride) as a raw material is excellent in heat resistance, but inferior in moldability, and the polyether imide obtained using an aromatic bis(etheric anhydride) as a raw material has a low heat resistance.
Many studies have been made to develop a polyimide excellent in moldability. For example, polyether imides are reported in Japanese Patent Application OPI (Kokai) Nos. 69196/1975 and 69197/1975. However, these polyimides exhibit an improved moldability, but have some problems in the heat resistance as the intrinsic character of polyimide.